Index: boost/date_time/posix_time/posix_time_io.hpp
===================================================================
--- boost/date_time/posix_time/posix_time_io.hpp	(revision 68583)
+++ boost/date_time/posix_time/posix_time_io.hpp	(working copy)
@@ -45,22 +45,25 @@
   std::basic_ostream<CharT, TraitsT>&
   operator<<(std::basic_ostream<CharT, TraitsT>& os,
              const ptime& p) {
-    boost::io::ios_flags_saver iflags(os);
-    typedef boost::date_time::time_facet<ptime, CharT> custom_ptime_facet;
-    typedef std::time_put<CharT>                  std_ptime_facet;
-    std::ostreambuf_iterator<CharT> oitr(os);
-    if (std::has_facet<custom_ptime_facet>(os.getloc()))
-      std::use_facet<custom_ptime_facet>(os.getloc()).put(oitr, os, os.fill(), p);
-    else {
-      //instantiate a custom facet for dealing with times since the user
-      //has not put one in the stream so far.  This is for efficiency 
-      //since we would always need to reconstruct for every time period
-      //if the locale did not already exist.  Of course this will be overridden
-      //if the user imbues as some later point.
-      custom_ptime_facet* f = new custom_ptime_facet();
-      std::locale l = std::locale(os.getloc(), f);
-      os.imbue(l);
-      f->put(oitr, os, os.fill(), p);
+    typename std::basic_ostream<CharT, TraitsT>::sentry no_error_sentry(os);
+    if (no_error_sentry) {
+      boost::io::ios_flags_saver iflags(os);
+      typedef boost::date_time::time_facet<ptime, CharT> custom_ptime_facet;
+      typedef std::time_put<CharT>                  std_ptime_facet;
+      std::ostreambuf_iterator<CharT> oitr(os);
+      if (std::has_facet<custom_ptime_facet>(os.getloc()))
+        std::use_facet<custom_ptime_facet>(os.getloc()).put(oitr, os, os.fill(), p);
+      else {
+        //instantiate a custom facet for dealing with times since the user
+        //has not put one in the stream so far.  This is for efficiency 
+        //since we would always need to reconstruct for every time period
+        //if the locale did not already exist.  Of course this will be overridden
+        //if the user imbues as some later point.
+        custom_ptime_facet* f = new custom_ptime_facet();
+        std::locale l = std::locale(os.getloc(), f);
+        os.imbue(l);
+        f->put(oitr, os, os.fill(), p);
+      }
     }
     return os;
   }
@@ -112,24 +115,27 @@
   std::basic_ostream<CharT, TraitsT>&
   operator<<(std::basic_ostream<CharT, TraitsT>& os,
              const boost::posix_time::time_period& p) {
-    boost::io::ios_flags_saver iflags(os);
-    typedef boost::date_time::time_facet<ptime, CharT> custom_ptime_facet;
-    typedef std::time_put<CharT>                  std_time_facet;
-    std::ostreambuf_iterator<CharT> oitr(os);
-    if (std::has_facet<custom_ptime_facet>(os.getloc())) {
-      std::use_facet<custom_ptime_facet>(os.getloc()).put(oitr, os, os.fill(), p);
+    typename std::basic_ostream<CharT, TraitsT>::sentry no_error_sentry(os);
+    if (no_error_sentry) {
+        boost::io::ios_flags_saver iflags(os);
+        typedef boost::date_time::time_facet<ptime, CharT> custom_ptime_facet;
+        typedef std::time_put<CharT>                  std_time_facet;
+        std::ostreambuf_iterator<CharT> oitr(os);
+        if (std::has_facet<custom_ptime_facet>(os.getloc())) {
+          std::use_facet<custom_ptime_facet>(os.getloc()).put(oitr, os, os.fill(), p);
+        }
+        else {
+          //instantiate a custom facet for dealing with periods since the user
+          //has not put one in the stream so far.  This is for efficiency 
+          //since we would always need to reconstruct for every time period
+          //if the local did not already exist.  Of course this will be overridden
+          //if the user imbues as some later point.
+          custom_ptime_facet* f = new custom_ptime_facet();
+          std::locale l = std::locale(os.getloc(), f);
+          os.imbue(l);
+          f->put(oitr, os, os.fill(), p);
+        }
     }
-    else {
-      //instantiate a custom facet for dealing with periods since the user
-      //has not put one in the stream so far.  This is for efficiency 
-      //since we would always need to reconstruct for every time period
-      //if the local did not already exist.  Of course this will be overridden
-      //if the user imbues as some later point.
-      custom_ptime_facet* f = new custom_ptime_facet();
-      std::locale l = std::locale(os.getloc(), f);
-      os.imbue(l);
-      f->put(oitr, os, os.fill(), p);
-    }
     return os;
   }
 
@@ -178,22 +184,25 @@
   std::basic_ostream<CharT, Traits>&
   operator<<(std::basic_ostream<CharT, Traits>& os, const time_duration& td)
   {
-    boost::io::ios_flags_saver iflags(os);
-    typedef boost::date_time::time_facet<ptime, CharT> custom_ptime_facet;
-    typedef std::time_put<CharT>                  std_ptime_facet;
-    std::ostreambuf_iterator<CharT> oitr(os);
-    if (std::has_facet<custom_ptime_facet>(os.getloc()))
-      std::use_facet<custom_ptime_facet>(os.getloc()).put(oitr, os, os.fill(), td);
-    else {
-      //instantiate a custom facet for dealing with times since the user
-      //has not put one in the stream so far.  This is for efficiency 
-      //since we would always need to reconstruct for every time period
-      //if the locale did not already exist.  Of course this will be overridden
-      //if the user imbues as some later point.
-      custom_ptime_facet* f = new custom_ptime_facet();
-      std::locale l = std::locale(os.getloc(), f);
-      os.imbue(l);
-      f->put(oitr, os, os.fill(), td);
+    typename std::basic_ostream<CharT, Traits>::sentry no_error_sentry(os);
+    if (no_error_sentry) {
+      boost::io::ios_flags_saver iflags(os);
+      typedef boost::date_time::time_facet<ptime, CharT> custom_ptime_facet;
+      typedef std::time_put<CharT>                  std_ptime_facet;
+      std::ostreambuf_iterator<CharT> oitr(os);
+      if (std::has_facet<custom_ptime_facet>(os.getloc()))
+        std::use_facet<custom_ptime_facet>(os.getloc()).put(oitr, os, os.fill(), td);
+      else {
+        //instantiate a custom facet for dealing with times since the user
+        //has not put one in the stream so far.  This is for efficiency 
+        //since we would always need to reconstruct for every time period
+        //if the locale did not already exist.  Of course this will be overridden
+        //if the user imbues as some later point.
+        custom_ptime_facet* f = new custom_ptime_facet();
+        std::locale l = std::locale(os.getloc(), f);
+        os.imbue(l);
+        f->put(oitr, os, os.fill(), td);
+      }
     }
     return os;
   }